X-ray diffraction photographs by Wilkins and Franklin suggested that O DNA molecules are arranged as a tightly coiled double helix
DNA and proteins have the same basic structure
O DNA is composed of either purines or pyrimidines, but not both
O DNA and RNA are the same molecules

Contrast how pollination is different among gymnosperms and angiosperms.

Amino acids contain the elements carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. of the 20 amino acids found in humans, 11 are called "nonessential" because they can be manufactured by the body when needed. which elements in these 11 amino acids are commonly obtained from the metabolism of sugar molecules?

What do your cells need to live? a. carbon dioxide b. carbon c. air d. oxygen